San Diego, USA to Helsinki is an approximately 16- hour flight. You can also do a combination of train and flight; or do a combination of flight and ferry. Traveling from San Diego to Helsinki, you'll lose 10 hours due to the time zone difference. Traveling from San Diego in April, things will get much colder in Helsinki: highs are around 47°F and lows about 32°F. Finish up your sightseeing early on the 28th (Sat) so you can go by car to Tampere.

Drive from Helsinki to Tampere in 2 hours. Alternatively, you can take a train; or take a bus. In April in Tampere, expect temperatures between 45°F during the day and 29°F at night. Finish your sightseeing early on the 29th (Sun) so you can take a train to Turku.

Take a train from Tampere to Turku in 2 hours. Alternatively, you can drive; or take a bus. April in Turku sees daily highs of 46°F and lows of 30°F at night. Wrap up your sightseeing by early afternoon on the 30th (Mon) to allow time for travel to Levi.

Traveling by flight from Turku to Levi takes 5 hours. Alternatively, you can do a combination of train and flight; or drive. Traveling from Turku in April, expect Levi to be slightly colder, temps between 38°F and 25°F. Finish your sightseeing early on the 2nd (Wed) to allow enough time to drive to Rovaniemi.

You can drive from Levi to Rovaniemi in 2.5 hours. Another option is to take a bus. In May in Rovaniemi, expect temperatures between 51°F during the day and 37°F at night. Wrap up your sightseeing by early afternoon on the 4th (Fri) to allow time for travel to Mustasaari.

Use the Route module to find suitable travel options from Rovaniemi to Mustasaari. Expect a daytime high around 56°F in May, and nighttime lows around 39°F. Finish up your sightseeing early on the 6th (Sun) so you can travel back home.